1. Field of the Invention
The invention relates to a halogen-free flame-retardant cable in which an outermost layer is formed of a resin composition of melamine cyanurate (MC) and a phosphorus compound blended into thermoplastic polyurethane (TPU and a layer excluding the outermost layer is formed of an ethylene-vinyl acetate copolymer (EVA), thereby suppressing a decrease in bond strength of an insulated wire with a cover layer and having high flame retardance.
2. Description of the Related Art
Thermoplastic polyurethane (TPU) is widely used as a cable coating material used for vehicles, robots or electrical equipments, etc., since it has excellent mechanical characteristics and flexibility at low temperature.
Various characteristics such as flame retardance, heat resistance or abrasion resistance are required for the cable used for the vehicles, robots or electrical equipments.
The major conventional resin composition is a resin composition in which a halogen-based flame retardant or an antimony compound including a bromine atom or a chlorine atom is blended into thermoplastic polyurethane (TPU) in order to obtain the flame retardance.
The resin composition obtained by the conventional art has a problem that harmful gas is generated from a halogen compound included in the flame retardant at the time of burning, or heavy metal blended into a material is eluted at the time of landfill.
JP-A 2007-95439 suggests to use thermoplastic polyurethane as a resin composition for the outermost layer of the cable and resin consisting mainly of an ethylene-vinyl acetate copolymer as a cover layer between an insulated wire and a sheath, and to cross-link the resin composition of the outermost layer by electron beam irradiation.